Originally Posted by rich
Ratinator has asked the fundamental question and until that is answered there won't be a proper solution.
It can't be to check for legality or compliance with the law; a field test can never deliver the precision needed for a test that would stand up to scrutiny in a court of law.
That leaves the matter of cheating.
Why would you want more power?
Insurance and reasonable steps to comply must come into the equation. As for cheating, I don't know, I'm sure that for some non FAC shooters maximum power is their holy grail. The advantage of a few more fps are, as you said negligible. A chrono on a course can only be there for two reasons. To deter anyone from cheating and to show compliance with insurance/ competition rules, albeit in house.